1. Field of the Invention
The invention relates to an electric portal axle for electrically driving a motor vehicle having two spur gear stages for driving two wheels of the axle.
2. Description of the Related Art
DE 10 2009 036 299 A1 discloses an electric portal axle that has two electric machines. A wheel is mounted rotatably in the region of each of the two ends of the portal axle and each wheel can be driven by a rotor of the electric machine assigned thereto. A downstep gear mechanism that is embodied as a spur gear stage is arranged between the respective electric machine and wheel assigned thereto. The input shaft of the respective spur gear stage is arranged closer to the ground on which the vehicle is standing than the output shaft of the spur gear stage. The region between the spur gear stages accordingly is positioned lower. As a result, the electric machines are positioned lower with respect to the underlying surface under the motor vehicle, thereby lowering the center of gravity of the motor vehicle.
An electric portal axle also can be configured so that the region between the spur gear stages is not lower, but instead is raised. As a result, the motor vehicle can be used off road.
Electrically drivable vehicles that have portal frames also are known from U.S. Pat. No. 6,843,750 B1, U.S. Pat. No. 6,978,853 B2 and U.S. Pat. No. 7,350,602 B2.
The object of the present invention is to provide an electric portal axle that can be shifted in two stages, for electrically driving a motor vehicle.